ABSTRACT This study aimed to evaluate the interplay between water hardness, sodium adsorption ratio (SAR), and electrical conductivity (EC); with tropical soil physical, chemical, and mineralogical characteristics on the displacement K + . The water quality treatments represented solutions suitable and not suitable for irrigation, with varying levels of water hardness (Q1 and Q2), low SAR and EC (Q3), low SAR and high EC (Q4), high SAR and EC (Q5), intermediate SAR and EC (Q6), and a deionized water control (Q7). Column experiments were conducted using constant head permeameters, collecting up to 20 pore volumes, when leaching occurred until this stage, with three replications. Displacement curves were fitted to the data, and multivariate statistical analyses were performed to allow understanding the relation among water and soil variables. The Q4 solution, classically considered suitable for irrigation, led to the displacement of K + in Inceptisol (I) but mostly in the Oxisol (O), and it may have occurred due to the high concentrations of cations in the solutions, that saturated their adsorption sites and chemically competed. Q5 solution, with high SAR and EC and classified as suitable for irrigation, induced a substantial K + displacement in Entisol Quartzipsamment (E); while even the solution with the highest hardness did not significantly affect the K + soil concentrations. Thus, it was determined that water classified as good quality for irrigation can induce K displacement in tropical soils, a detrimental effect.
Alvarez et al. (Mon,) studied this question.